Ubuntu File Permission modification command

Sudo chmod 600 ××× (only the owner has read and write permissions)

Sudo chmod 644 ××× (the owner has the read and write permissions, and the group user only has the read permission)

Sudo chmod 700 ××× (only the owner has the permission to read, write, and execute the CHMOD)

Sudo chmod 666 ××× (everyone has read and write permissions)

Sudo chmod 777 ××× (everyone has the permission to read, write, and execute the CHMOD)

Method 1:
Syntax format: chmod [-VR] mode file name
Parameter description:
Mode permission setting string, in the format of [ugoa] [+-=] [rwx]
U indicates the file owner.
G indicates that the file owner belongs to a group.
O indicates others
A indicates that the preceding three elements are file owner (u), group (G), and others (o)
+ Adds permissions.
-Indicates that the permission is revoked.
= Indicates the unique permission setting.
R indicates that you have read permission.
W indicates that you have the write permission.
X indicates that you have the execution permission.
-V: displays details about permission changes.
-R indicates that all files and subdirectories in the current directory are modified with the same permissions.